The Golden Gate Bridge District board voted 15-0 Friday to approve the purchase of a $26.5 million median traffic barrier to prevent potentially deadly head-on accidents.

The project will be funded by the Metropolitan Transportation Commission, which will administer $20 million in federal grants. Toll revenue and other grant funds will cover the balance.

The barrier will take about a year to build, and be put in place in October or November of 2014.

Because the barrier needs to be assembled on the span, the bridge will be closed for 52 hours from a Friday night to a Monday morning. The bridge has been closed only for weather, and never for more than three hours, bridge officials said. In 1987 it was closed to vehicle traffic for the span's 50th birthday, but was open to pedestrians.